CN107430073B

CN107430073B - Functional water concentration sensor

Info

Publication number: CN107430073B
Application number: CN201680019182.4A
Authority: CN
Inventors: 末广善文; 马场徹; 奥村真; 吉原孝明
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2015-07-10
Filing date: 2016-06-15
Publication date: 2020-12-15
Anticipated expiration: 2036-06-15
Also published as: WO2017010043A1; US20180284014A1; EP3321664A4; CN107430073A; US10180395B2; JPWO2017010043A1; JP6575827B2; EP3321664B1; EP3321664A1

Abstract

A functional water concentration sensor (1) is provided with: a container (40) for putting functional water (90); a light source (10) that emits ultraviolet light (11); a fluorescent body (20) that emits fluorescence (21) when excited by ultraviolet light (11) emitted from a light source (10) and passing through the inside of the container (40); and a light receiving element (30) that receives the fluorescence (21), wherein the peak wavelength of the ultraviolet light (11) emitted by the light source (10) is within a predetermined range that includes an absorption peak specific to the functional water (90).

Description

Functional water concentration sensor

Technical Field

The invention relates to a functional water concentration sensor.

Background

Conventionally, ozone has been used for sterilization, deodorization, decolorization, and the like. Ozone has a strong oxidizing power, and therefore, its concentration needs to be controlled. Therefore, an ozone concentration meter for measuring the concentration of ozone has been developed. For example, a light absorption type ozone concentration meter described in patent document 1 irradiates ultraviolet light to a sample tube containing a sample, and detects the intensity of transmitted light transmitted through the sample tube, thereby measuring the ozone concentration.

(Prior art document)

(patent document)

Patent document 1: japanese laid-open patent publication No. 2002-5826

Further, it is necessary to detect the concentration of functional water having a predetermined function in addition to ozone by a small and inexpensive sensor. The sensor may be small, and may be mounted to a sterilization apparatus using functional water having sterilization capability, for example. By detecting the concentration of the functional water in the sterilization apparatus, it is possible to appropriately recognize the decrease in the sterilization capability of the sterilization apparatus and the like. However, for example, the conventional ozone concentration meter described above uses an expensive photodiode having sensitivity in the ultraviolet region, and thus cannot realize a small and inexpensive sensor.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a small and inexpensive functional water concentration sensor.

In order to achieve the above object, a functional water concentration sensor according to one embodiment of the present invention includes: a container for putting functional water; a light source emitting ultraviolet light; a phosphor excited by ultraviolet light emitted from the light source and passing through the inside of the container, thereby emitting fluorescence; and a light receiving element for receiving the fluorescence, wherein a peak wavelength of ultraviolet light emitted from the light source is within a predetermined range including an absorption peak specific to the functional water.

According to the present invention, a small and inexpensive functional water concentration sensor can be provided.

Drawings

Fig. 1 is a schematic diagram showing the structure of a functional water concentration sensor according to embodiment 1 of the present invention.

Fig. 2 is a schematic diagram for explaining the operation of the functional water concentration sensor according to embodiment 1 of the present invention.

Fig. 3 is a graph showing a spectrum of fluorescence of an example of the phosphor according to example 1 of the present invention.

Fig. 4 is a graph showing a spectrum of fluorescence of another example of the phosphor according to example 1 of the present invention.

Fig. 5A is a graph showing an absorption spectrum of hypochlorous acid water at each concentration according to example 1 of the present invention.

Fig. 5B is a graph showing the transmittance of ultraviolet light with respect to the concentration of hypochlorous acid water in example 1 of the present invention.

Fig. 6A is a graph showing an absorption spectrum of each concentration of ozone water according to example 1 of the present invention.

Fig. 6B is a graph showing the transmittance of ultraviolet light with respect to the concentration of ozone water according to example 1 of the present invention.

Fig. 7 is a graph showing the relationship between the concentration of hypochlorous acid water and the transmittance of ultraviolet light in the case where no phosphor is provided according to example 1 of the present invention.

Fig. 8 is a graph showing the relationship between the concentration of hypochlorous acid water and the transmittance of ultraviolet light in example 1 of the present invention.

Fig. 9 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 1 of embodiment 1 of the present invention.

Fig. 10 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 2 of embodiment 1 of the present invention.

Fig. 11 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 3 of embodiment 1 of the present invention.

Fig. 12 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 4 of embodiment 1 of the present invention.

Fig. 13 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to embodiment 2 of the present invention.

Fig. 14 is a graph showing the transmittance of ultraviolet light with respect to the concentration of ozone water for each optical path length of the functional water concentration sensor according to embodiment 2 of the present invention.

Fig. 15 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 1 of embodiment 2 of the present invention.

Fig. 16 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 2 of embodiment 2 of the present invention.

Fig. 17 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 3 of embodiment 2 of the present invention.

Fig. 18 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 4 of embodiment 2 of the present invention.

Fig. 19 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor according to modification 5 of embodiment 2 of the present invention.

Fig. 20 is a schematic diagram showing a configuration of a functional water concentration sensor according to embodiment 3 of the present invention.

Fig. 21 is a schematic diagram showing the structure of the functional water concentration sensor according to modification 1 of embodiment 3 of the present invention.

Fig. 22 is a schematic diagram showing the structure of the functional water concentration sensor according to modification 2 of embodiment 3 of the present invention.

Fig. 23 is a schematic diagram showing the structure of a functional water concentration sensor according to modification 3 of embodiment 3 of the present invention.

Detailed Description

Hereinafter, a functional water concentration sensor according to an embodiment of the present invention will be described in detail with reference to the drawings. The embodiments described below are each a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement and connection forms of the constituent elements, steps, order of the steps, and the like shown in the following embodiments are merely examples and do not limit the spirit of the present invention. Therefore, among the constituent elements of the following examples, constituent elements that are not described in the embodiments showing the uppermost concept of the present invention are described as arbitrary constituent elements.

Each drawing is a schematic drawing, and is not necessarily a strictly illustrated drawing. In each drawing, the same components are denoted by the same reference numerals. In the following embodiments, expressions such as substantially all or substantially the same are used. For example, the substantial agreement means not only complete agreement but also actual agreement, and includes an error of about several%. The same applies to other expressions using "approximate".

(example 1)

[ outline of functional Water concentration sensor ]

First, an outline of the functional water concentration sensor according to the present embodiment will be described with reference to fig. 1 and 2. Fig. 1 is a schematic diagram showing the structure of a functional water concentration sensor 1 according to the present embodiment. Fig. 2 is a schematic diagram for explaining the operation of the functional water concentration sensor 1 according to the present embodiment.

The functional water concentration sensor 1 according to the present embodiment is a sensor that measures the concentration of the functional water 90 placed in the container 40. Specifically, the functional water concentration sensor 1 irradiates ultraviolet light to the functional water 90, and converts the wavelength of the ultraviolet light (transmitted light) absorbed by the fluorescent material 20 during transmission of the functional water 90. The functional water concentration sensor 1 detects the wavelength-converted light (for example, visible light) to measure the concentration of the functional water 90.

The functional water 90 is water to which a scientific basis for treatment and function is clarified and will be clarified among aqueous solutions to which a reproducible and useful function is imparted by artificial treatment. Specifically, the functional water 90 is hypochlorous acid water, ozone water, or the like.

As shown in fig. 1, the functional water concentration sensor 1 according to the present embodiment includes a light source 10, a fluorescent material 20, a light receiving element 30, a container 40, and a control circuit 50. Although not shown in fig. 1, the functional water concentration sensor 1 is housed in a light-shielding case in order to prevent external light from entering the light-receiving element 30. At this time, the inner surface of the case may also be formed of an ultraviolet light absorbing material to absorb light (i.e., diffused light) that is not incident on the incident window 41 among the ultraviolet light 11 emitted from the light source 10.

The respective constituent elements of the functional water concentration sensor 1 will be described in detail below.

[ light Source ]

The light source 10 emits ultraviolet light 11. The ultraviolet light 11 is, for example, light having a peak wavelength of 350nm or less. Details of the ultraviolet light 11 will be described later.

The light source 10 may be configured to be able to change the peak wavelength of the ultraviolet light 11. Specifically, the light source 10 may emit ultraviolet light 11 having different peak wavelengths according to the functional water 90 to be measured. That is, the light source 10 may emit light having a peak wavelength predetermined according to the absorption spectrum specific to the functional water 90 as the ultraviolet light 11.

The light source 10 is a solid-state light Emitting element such as an led (light Emitting diode) element, but is not limited thereto. The light source 10 may be a semiconductor laser, a small mercury lamp, or the like.

As shown in fig. 1, a light source 10 is arranged close to an entrance window 41 of a container 40. Close means that the distance between each other is within a predetermined range, including the case of contact. For example, the light source 10 is disposed so that the distance from the entrance window 41 is within 5 mm. That is, the light source 10 is configured such that substantially all of the emitted ultraviolet light 11 is incident on the entrance window 41, that is, the emitted ultraviolet light 11 is hardly exposed to the outside of the container 40. The ultraviolet light 11 from the light source 10, as shown in fig. 2, is incident in a substantially perpendicular manner with respect to the entrance window 41. The distance between the light source 10 and the entrance window 41 is not limited to 5mm or less, and is not particularly limited.

[ phosphor ]

The fluorescent material 20 is excited by the ultraviolet light 11 emitted from the light source 10 and passing through the container 40, and emits fluorescent light 21. Specifically, the fluorescent material 20 converts the wavelength of the ultraviolet light 11 (transmitted light) transmitted through the functional water 90, and emits the wavelength-converted light as the fluorescent light 21. The fluorescence 21 is, for example, visible light. Specifically, the phosphor 20 receives the ultraviolet light 11 and emits fluorescence 21 having a peak wavelength in the visible light region (380nm to 780 nm).

The fluorescent material 20 may emit light having a peak wavelength corresponding to the sensitivity of the light receiving element 30 as the fluorescent light 21. Specifically, the fluorescent material 20 emits fluorescent light 21 having a peak wavelength in a wavelength region where the sensitivity of the light receiving element 30 is high. For example, when the light receiving element 30 has high sensitivity in the green region (500nm to 570nm), the phosphor 20 may emit light having a peak wavelength in a range of 500nm to 570nm as the fluorescence 21.

Fig. 3 and 4 are graphs showing spectra of fluorescence of an example of the fluorescent material 20 according to the present embodiment. In fig. 3 and 4, the spectrum of the ultraviolet light 11 as the excitation light is shown by a broken line, and the spectrum of the fluorescence 21 is shown by a solid line.

The phosphor 20 shown in FIG. 3 is YPV phosphor (europium-activated yttrium phosphovanadate; Y (P, V) O₄：Eu³⁺). As shown in fig. 3, the phosphor 20 emits fluorescent light 21 (red light) having a peak wavelength at approximately 620nm when it receives ultraviolet light 11 of 350nm or less.

The phosphor 20 shown in FIG. 4 is a LAP phosphor (cerium terbium-activated lanthanum phosphate phosphor; LaPO)₄：Ce³⁺，Tb³⁺). As shown in fig. 4, the phosphor 20 emits fluorescent light 21 (green light) having a peak wavelength at approximately 550nm when it receives ultraviolet light 11 of 300nm or less.

In the present embodiment, the phosphor 20 is provided on a translucent plate such as a glass plate disposed close to the exit window 42, for example. Specifically, the fluorescent material 20 is contained in a resin material coated on the surface of the glass plate. Alternatively, the phosphor 20 may be dispersed and contained in the glass plate. Alternatively, the phosphor 20 may be dispersed and contained in a plate-like ceramic (e.g., alumina or the like).

[ light-receiving element ]

The light receiving element 30 receives the fluorescence 21. Specifically, the light receiving element 30 photoelectrically converts the received fluorescence 21 to generate an electric signal corresponding to the amount (i.e., intensity) of the received fluorescence 21. The generated electric signal is output to the control circuit 50.

The light receiving element 30 has high sensitivity in a predetermined wavelength range. In the present embodiment, the light receiving element 30 has high sensitivity in the visible light region. That is, the light receiving element 30 has a higher sensitivity to visible light than to ultraviolet light. The light receiving element 30 may not have sensitivity in the ultraviolet region (380nm or less).

The light receiving element 30 is, for example, a photodiode, but is not limited thereto. The light receiving element 30 may be a phototransistor or the like. As the light receiving element 30, a general-purpose inexpensive photodiode having almost no sensitivity in the ultraviolet region can be used.

The light receiving element 30 is disposed close to the phosphor 20. For example, the light receiving element 30 is disposed within a distance of 5mm from the fluorescent material 20, or is disposed in contact with the fluorescent material 20. Specifically, the light receiving element 30 is arranged to receive substantially all of the light traveling toward the light receiving element 30 from among the fluorescent light 21 emitted from the fluorescent material 20. The distance between the light receiving element 30 and the phosphor 20 is not limited to 5mm or less, and is not particularly limited.

[ Container ]

The container 40 is a container into which the functional water 90 is put. The container 40 is, for example, a bottomed cylindrical tube such as a bottomed cylinder or a bottomed square tube, but is not particularly limited. The container 40 includes two transmission windows through which the ultraviolet light 11 is transmitted. Specifically, as shown in fig. 1, the container 40 includes an entrance window 41 and an exit window 42.

The entrance window 41 is a window into which the ultraviolet light 11 emitted from the light source 10 enters. The entrance window 41 is formed of a light transmitting member that is provided at an opening formed in the container 40 and transmits the ultraviolet light 11. The entrance window 41 (light transmitting member) is formed of, for example, quartz glass, sapphire glass, or the like. Specifically, the entrance window 41 is formed of a plate-shaped glass having substantially planar entrance and exit surfaces. The ultraviolet light 11 is incident substantially perpendicularly to the entrance window 41. Specifically, the ultraviolet light 11 enters along the thickness direction of the plate-shaped glass (entrance window 41). That is, the ultraviolet light 11 is incident in the normal direction of the incident surface.

The emission window 42 is a window through which the ultraviolet light 11 incident on the container 40 is emitted to the phosphor 20. The emission window 42 is formed of a transparent member that is provided in an opening formed in the container 40 and transmits the ultraviolet light 11 therethrough. The emission window 42 (light transmitting member) is formed of, for example, quartz glass, sapphire glass, or the like. Specifically, the emission window 42 is formed of a plate-shaped glass having substantially planar incident and emission surfaces. The ultraviolet light 11 is emitted substantially perpendicularly from the emission window 42. Specifically, the ultraviolet light 11 is emitted along the thickness direction of the plate-shaped glass (the emission window 42). That is, the ultraviolet light 11 is emitted in the normal direction of the emission surface.

In the present embodiment, the main body of the container 40 (specifically, the portions other than the two transmission windows) is formed of a material that shields (absorbs or reflects) ultraviolet light. For example, the main body of the container 40 is made of a resin material such as acrylic (PMMA) or Polycarbonate (PC), or a metal material. The entire container 40 may be transparent to the ultraviolet light 11. Specifically, the entire container 40 may be formed of quartz glass or the like.

In the present embodiment, the light source 10, the container 40, the fluorescent material 20, and the light receiving element 30 are arranged on the same straight line in this order. As shown in fig. 1, the entrance window 41 and the exit window 42 of the container 40 are also arranged on the straight line. Accordingly, as shown in fig. 2, the ultraviolet light 11 emitted from the light source 10 is converted in wavelength by the fluorescent material 20 in the middle, but reaches the light receiving element 30 at the shortest distance. Therefore, the occurrence of light leakage (stray light) between the light source 10 and the light receiving element 30 can be suppressed, whereby the intensity of the fluorescence 21 can be detected with high accuracy, and the concentration of the functional water 90 can be measured with high accuracy.

The container 40 may be a part of a predetermined pipe. Specifically, the functional water 90 may flow in the container 40. For example, the functional water 90 may be circulated between the container 40 and a reaction tank (not shown). The reaction tank is a container for allowing the functional water 90 to function. For example, when the functional water 90 has a function of sterilization, deodorization, or the like, the functional water 90 comes into contact with an object (for example, a gas such as air) in the reaction tank, and performs sterilization, deodorization, or the like of the object. In this case, the functional water 90 performs sterilization, deodorization, and the like, and the functional water concentration sensor 1 can measure the concentration of the functional water 90. That is, the functional water concentration sensor 1 can be used by being attached to a deodorization device or the like.

[ control Circuit ]

The control circuit 50 is a controller that controls the light source 10 and the light receiving element 30. The control circuit 50 includes a nonvolatile memory in which a program is stored, a volatile memory which is a temporary storage area for executing the program, an input/output port, a processor for executing the program, and the like. The control circuit 50 is realized by, for example, a microcomputer (microcontroller) or the like.

The control circuit 50 measures (calculates) the concentration of the functional water 90 based on the electric signal output from the light receiving element 30. Specifically, the control circuit 50 calculates the intensity of the fluorescence 21 from the electric signal, and calculates the transmittance (or absorbance) of the functional water 90 from the calculated intensity of the fluorescence 21. The control circuit 50 calculates the concentration of the functional water 90 from the calculated transmittance according to lambert beer's law, which will be described later. The control circuit 50 may be configured such that the memory stores a table in which the intensity of the fluorescence 21 is associated with the concentration of the functional water 90, and the concentration of the functional water 90 is determined by referring to the table.

The control circuit 50 may control the light source 10 to be turned on or off, the intensity and wavelength of the ultraviolet light 11, and the like. That is, the control circuit 50 causes the light source 10 to emit the ultraviolet light 11 at a predetermined intensity and wavelength at a predetermined timing in accordance with a user instruction, a program, or the like. For example, the control circuit 50 may change the intensity and wavelength of the ultraviolet light 11 according to the type of the functional water 90.

The control circuit 50 may perform feedback control of the light source 10 based on the measurement result of the concentration of the functional water 90. For example, when the amount of light received by the light receiving element 30 is too small, that is, when the concentration of the functional water 90 is too high, the intensity of the ultraviolet light 11 may be increased or the wavelength may be varied.

[ ultraviolet light ]

Next, the ultraviolet light 11 emitted from the light source 10 according to the present embodiment will be described in detail.

The peak wavelength of the ultraviolet light 11 emitted from the light source 10 (ultraviolet light before the functional water 90 is transmitted) is within a predetermined range including the absorption peak specific to the functional water 90. The absorption peak is a wavelength showing a maximum value of absorbance in the absorption spectrum of the functional water 90. In other words, the absorption peak is a wavelength of light having an extremely large absorption amount by the functional water 90.

Here, the concentration of the functional water 90 and the absorption of the ultraviolet light 11 by the functional water 90 are shownThe relationship of degree. Generally, the intensity of light before entering a medium is defined as I according to lambert beer's law₀When the intensity of light after passing through the medium having the length L is represented by I, the following (formula 1) and (formula 2) are satisfied.

(number formula 1)

(formula 1)

(formula 2) Absorbance ═ 1-transmittance

Here, "a" is the absorption coefficient and "C" is the molar concentration of the medium. "L" is the length (i.e., optical path length) of the medium (i.e., functional water 90) through which the ultraviolet light 11 is transmitted, and corresponds to the distance from the entrance window 41 to the exit window 42 of the container 40 in the present embodiment.

The absorbance indicates the absorbance of the ultraviolet light 11 by the functional water 90, and the larger the value, the more the absorption by the functional water 90 is strong. For example, if the absorbance is "1", it indicates that all of the ultraviolet light 11 is absorbed, and if the absorbance is "0", it indicates that the ultraviolet light 11 is not absorbed at all. Also, the transmittance shows the transmittance of the ultraviolet light 11 based on the functional water 90.

Fig. 5A is a graph showing an absorption spectrum of hypochlorous acid water according to the present embodiment at each concentration. In fig. 5A, the horizontal axis shows the wavelength of light (ultraviolet light 11) irradiated to the functional water 90 (hypochlorous acid water), and the vertical axis shows the absorbance of the functional water 90.

As shown in fig. 5A, hypochlorous acid water has an absorption peak at about 292nm, regardless of the concentration thereof, and absorbs a large amount of light in a predetermined range including the absorption peak. The predetermined range is a range having an absorbance at a predetermined ratio or more of the absorbance at the absorption peak. The specified ratio is, for example, 5% to 20%. For example, the ultraviolet light that hypochlorous acid water can absorb is within a predetermined range of 250nm to 350 nm. Therefore, in the present embodiment, when the functional water 90 is hypochlorous acid water, the light source 10 emits ultraviolet light 11 having a peak wavelength in a range of 250nm to 350 nm.

In a predetermined range including an absorption peak, the higher the concentration of hypochlorous acid water is, the smaller the concentration is, with respect to the absorbance of light having a predetermined wavelength. As shown in FIG. 5A, this tendency remarkably appears in the vicinity of about 292nm, which is an absorption peak.

Fig. 5B is a graph showing the transmittance of ultraviolet light with respect to the concentration of hypochlorous acid water according to the present embodiment. In fig. 5B, the horizontal axis shows the concentration of the functional water 90, and the vertical axis shows the transmittance of the functional water 90 with respect to the ultraviolet light 11.

In fig. 5B, black circles are measured values, and the solid lines and the broken lines show an exponential approximation curve of the measured values obtained by the least square method according to (equation 1).

Further, light having a wavelength of 292nm has a larger ratio of change in transmittance with respect to change in concentration than light having a wavelength of 275 nm. That is, the ultraviolet light 11 is light having an absorption peak in the absorption spectrum close to, and the concentration of the functional water 90 can be easily calculated from the transmittance.

Fig. 6A is a graph showing an absorption spectrum of each concentration of ozone water according to the present embodiment. In fig. 6A, the horizontal axis shows the wavelength of light (ultraviolet light 11) irradiated to the functional water 90 (ozone water), and the vertical axis shows the absorbance of the functional water 90.

As shown in fig. 6A, the ozone water has an absorption peak at about 260nm regardless of the concentration thereof, and absorbs a large amount of light in a predetermined range including the absorption peak. For example, the predetermined range of ultraviolet light that can be absorbed by ozone water is 220nm to 300 nm. Therefore, in the present embodiment, when the functional water 90 is ozone water, the light source 10 emits ultraviolet light 11 having a peak wavelength in a range of 220nm to 300 nm.

In a predetermined range including an absorption peak, the higher the concentration of ozone water is, the lower the concentration is, the higher the absorbance at a predetermined wavelength is, as in the case of hypochlorous acid water. As shown in fig. 6A, this tendency appears remarkably near about 260nm, which is an absorption peak.

Fig. 6B is a graph showing the transmittance of ultraviolet light with respect to the concentration of ozone water according to the present embodiment. In fig. 6B, the horizontal axis shows the concentration of the functional water 90, and the vertical axis shows the transmittance of the functional water 90 with respect to the ultraviolet light 11. The black circles indicate measured values, and the solid lines indicate an exponential approximation curve of the measured values obtained by the least square method.

Fig. 6B shows the transmittance with respect to the ozone concentration when light having a wavelength of 260nm is irradiated. As shown in fig. 6B, the higher the ozone concentration, the smaller the transmittance.

As shown in fig. 5B and 6B, the transmittance and the concentration of the functional water 90 have a dependency relationship with each other according to the lambert beer law. Therefore, the intensity of the incident light before the functional water 90 is transmitted and the intensity of the transmitted light (emitted light) after the functional water 90 is transmitted are obtained, and the absorbance (or transmittance) based on the functional water 90 can be calculated according to (equation 1).

As described above, in the present embodiment, when the functional water 90 is hypochlorous acid water, the light source 10 emits light having a peak wavelength in a range of 250nm to 350nm as the ultraviolet light 11. For example, the light source 10 emits light having a peak wavelength of 275nm as the ultraviolet light 11.

When the functional water 90 is ozone water, the light source 10 emits light having a peak wavelength in a range of 220nm to 300nm as the ultraviolet light 11. For example, the light source 10 emits light having a peak wavelength of 260nm as the ultraviolet light 11.

[ measurement of concentration of functional Water ]

As described above, in the present embodiment, the concentration of the functional water 90 is measured from the intensity before the incidence of the ultraviolet light 11 and the intensity after the transmission. Specifically, instead of directly detecting the ultraviolet light 11 as the transmitted light, the fluorescent material 20 converts the ultraviolet light into the fluorescence 21, and then the light receiving element 30 detects the converted fluorescence 21. In the present embodiment, the intensity of the fluorescence 21 is used instead of the intensity of the transmitted light (ultraviolet light 11) to measure the concentration of the functional water 90.

First, the result of directly detecting the intensity of the ultraviolet light 11 after transmission without using the phosphor 20 in order to confirm that the concentration of the functional water 90 can be accurately measured from the intensity of the ultraviolet light 11 will be described with reference to fig. 7.

Fig. 7 is a graph showing the relationship between the concentration of hypochlorous acid water and the transmittance of ultraviolet light 11 in the case where the fluorescent material 20 is not provided according to the present embodiment. In fig. 7, black circles and black triangles show measured values, and a solid line shows an exponential approximation curve of the measured values obtained by the least square method.

In fig. 7, the transmitted light (ultraviolet light 11) emitted from the emission window 42 is detected by a photodiode having sensitivity in the ultraviolet region without the fluorescent material 20. Fig. 7 (a) shows the case where the peak wavelength of the ultraviolet light 11 is 275nm, which is the same as the graph shown in fig. 5B. Fig. 7 (b) is a graph in which the vertical axis of the graph shown in (a) is logarithmically converted.

In the case according to lambert beer's law, as shown in (equation 1), the transmittance is expressed as an exponential function of the concentration. Therefore, on the logarithmic graph, the relationship between the transmittance and the concentration is represented by a straight line. As shown in fig. 7 (b), it is found that the concentration of the functional water 90 can be measured by detecting the ultraviolet light 11 in which the actual measurement values (black dots and black triangles) substantially coincide with the approximate straight line.

Next, the results of using the fluorescent material 20 will be described with reference to fig. 8.

Fig. 8 is a graph showing the relationship between the concentration of hypochlorous acid water and the transmittance of ultraviolet light according to the present example. In fig. 8, the four black corners show measured values, and the solid line shows an exponential approximation curve of the measured values obtained by the least square method.

In fig. 8, YPV phosphor was used as the phosphor 20. The phosphor 20 emits fluorescent light 21 having an intensity corresponding to the intensity of the ultraviolet light 11 as the excitation light. Specifically, the ultraviolet light 11 as the excitation light has a proportional relationship with the fluorescence 21. Therefore, the control circuit 50 converts the intensity of the fluorescence 21 detected by the light receiving element 30 into the intensity of the ultraviolet light 11, and calculates the transmittance of the ultraviolet light 11.

Fig. 8 (a) shows a case where the peak wavelength of the ultraviolet light 11 is 275nm, and fig. 8 (b) is a graph obtained by converting the graph shown in (a) into a logarithmic graph. As shown in fig. 8 (b), when the fluorescence 21 is detected, the measured value (black four corners) substantially coincides with the approximate curve (solid line) as in the case of directly detecting the ultraviolet light 11. Therefore, it is known that the concentration of the functional water 90 can be measured by detecting the fluorescence 21. That is, it is known that direct detection of the ultraviolet light 11 is not necessary.

[ Effect and the like ]

As described above, the functional water concentration sensor 1 according to the present embodiment includes: a container 40 into which the functional water 90 is put; a light source 10 emitting ultraviolet light 11; a phosphor 20 that is excited by ultraviolet light 11 emitted from the light source 10 and passing through the inside of the container 40 to emit fluorescence 21; and a light receiving element 30 for receiving the fluorescence 21, wherein the peak wavelength of the ultraviolet light 11 emitted from the light source 10 is within a predetermined range including an absorption peak specific to the functional water 90.

In this way, the fluorescent material 20 performs wavelength conversion of the ultraviolet light 11 to emit the fluorescent light 21, and the light receiving element 30 receives the fluorescent light 21 emitted from the fluorescent material 20. The fluorescence 21 is light having a longer wavelength than the ultraviolet light 11, and is visible light, for example. Therefore, the light receiving element 30 does not need to have sensitivity in the ultraviolet region, and an inexpensive photodiode having sensitivity in the visible light region can be used.

Further, since a small-sized and long-life LED element or the like can be used as the light source 10, the functional water concentration sensor 1 can be made small-sized and long-life.

Further, in the present embodiment, the ultraviolet light 11 emitted from the light source 10 is determined, for example, based on the absorption spectrum specific to the functional water 90 so as to include a peak wavelength in a predetermined range including the absorption peak specific to the functional water 90. That is, the ultraviolet light 11 is absorbed by the functional water 90, and a change in the intensity of the ultraviolet light 11 is detected, thereby measuring the concentration of the functional water 90. Therefore, it is not necessary to add a substance such as a detection agent for the purpose of measuring the concentration to the functional water 90. Therefore, the functional water 90 does not react with the detection agent to change chemically, and therefore, even the functional water 90 after the concentration measurement (after the ultraviolet light 11 irradiation) can exhibit the original function. That is, the functional water concentration sensor 1 can measure the concentration while maintaining the function of the functional water 90, and therefore, can be mounted to a device or the like using the functional water 90.

For example, when the functional water 90 is a liquid having a sterilizing ability such as hypochlorous acid water, the sterilizing ability of the functional water 90 is not lost, and therefore the functional water 90 can be used for sterilization as it is. For example, since the concentration can be measured and sterilized while circulating the functional water 90, feedback control can be performed in which the measurement result of the concentration is reflected in the sterilization or the like. In this way, the functional water concentration sensor 1 can be mounted to a device such as a sterilization apparatus.

At this time, for example, when the concentration of the functional water 90 decreases because the functional water 90 is used for sterilization or the like, feedback control of the additional functional water 90 or the like is performed. This can increase the concentration of the functional water 90 and sufficiently exhibit the function of sterilization and the like. Further, according to the feedback control, the functional water 90 can be prevented from having an excessively high concentration, and the generation of harmful gas, odor gas, or the like can be prevented.

The fluorescent material 20 emits light having a peak wavelength corresponding to the sensitivity of the light receiving element 30 as the fluorescent light 21, for example.

Accordingly, for example, a region of the light receiving element 30 having high sensitivity can be effectively used, and thus the range of the amount of light that can be detected is expanded. Therefore, the range of the concentration that can be measured can be expanded, or the accuracy of the concentration measurement can be improved.

In the present embodiment, the fluorescent material 20 uniformly emits fluorescent light in all directions. That is, since the fluorescent light 21 emitted from the fluorescent material 20 is emitted in all directions, the light amount of the fluorescent light 21 received by the light receiving element 30 is reduced when the fluorescent material 20 and the light receiving element 30 are separated from each other.

In contrast, in the functional water concentration sensor 1 according to the present embodiment, for example, the light receiving element 30 is disposed close to the fluorescent material 20.

Accordingly, the amount of light incident on the light receiving element 30 among the fluorescent light 21 emitted from the fluorescent material 20 can be increased, and thus detection can be performed even when the fluorescent light 21 is weak. Therefore, the range of the concentration that can be measured can be expanded. Further, light (stray light) that travels inside a housing (not shown) of the functional water concentration sensor 1 without being incident on the light receiving element 30 can be reduced. Therefore, detection errors due to the stray light entering the light receiving element 30 can be suppressed, and the fluorescence 21 can be detected with high accuracy.

For example, the light source 10, the container 40, the fluorescent material 20, and the light receiving element 30 are arranged in this order on substantially the same straight line.

Accordingly, it is not necessary to change the traveling direction of the ultraviolet light 11 or the fluorescent light 21 by reflection, refraction, or the like, and therefore, downsizing and cost reduction can be achieved without providing a member such as a lens or a mirror. When the traveling direction of light is changed by a member such as a lens or a mirror, the amount of fluorescent light 21 incident on the light receiving element 30 may be reduced by the generation of stray light, absorption of light by the member, or the like. On the other hand, since the functional water concentration sensor 1 does not include a lens, a mirror, or the like, it is possible to suppress a decrease in the amount of the fluorescence 21 incident on the light receiving element 30, and to measure the concentration of the functional water 90 with high accuracy.

For example, the container 40 includes an entrance window 41 through which the ultraviolet light 11 emitted from the light source 10 enters, and the ultraviolet light 11 from the light source 10 enters the entrance window 41 substantially perpendicularly.

This can suppress refraction and reflection of the ultraviolet light 11 on the incident surface of the incident window 41. That is, since the functional water 90 in the container 40 can be efficiently irradiated with the light emitted from the light source 10, the concentration of the functional water 90 can be measured with high accuracy.

Hereinafter, a modified example of the functional water concentration sensor 1 according to the present embodiment will be described with reference to the drawings. In the description of the respective modifications, the same points as those of the functional water concentration sensor 1 according to the present embodiment will be omitted or simplified.

[ modification 1]

Fig. 9 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 1a according to modification 1 of the present embodiment.

The functional water concentration sensor 1a according to the present modification is different from the functional water concentration sensor 1 shown in fig. 1 in that a slit portion 60 is newly provided.

The slit section 60 is provided between the light source 10 and the entrance window 41, and limits the irradiation range of the ultraviolet light 11. Specifically, the slit section 60 has an opening having substantially the same shape as the entrance window 41. The slit portion 60 is, for example, a plate provided with an opening (slit). The slit section 60 is provided such that the opening substantially coincides with the entrance window 41 when viewed from the light source 10.

The slit portion 60 is formed of a material that blocks (reflects or absorbs) the ultraviolet light 11. The slit portion 60 is formed of, for example, the same material as the main body of the container 40.

In the functional water concentration sensor 1a according to the modification, light emitted from the ultraviolet light 11 emitted from the light source 10 to the outside of the opening is blocked by the slit portion 60 and does not travel into the container 40. The light passing through the opening enters the entrance window 41, and the functional water 90 is transmitted and then exits from the exit window 42. In this way, stray light generated by irradiation of the unnecessary region with ultraviolet light can be reduced, and detection accuracy can be improved.

[ modification 2]

Fig. 10 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 1b according to modification 2 of the present embodiment.

The functional water concentration sensor 1b according to the present modification is different from the functional water concentration sensor 1 shown in fig. 1 in that a lens portion 61 is newly provided.

The lens unit 61 is provided between the light source 10 and the entrance window 41, and suppresses the divergence of the ultraviolet light 11. The lens unit 61 is, for example, a condenser lens for condensing the ultraviolet light 11 on the fluorescent material 20, or a collimator lens for emitting the ultraviolet light 11 as parallel light. The lens portion 61 is formed of, for example, translucent quartz glass.

As described above, according to the functional water concentration sensor 1b of the present modification example, since the amount of ultraviolet light 11 that transmits functional water 90 can be increased, the range of measurable concentrations can be expanded, or the accuracy of concentration measurement can be improved.

[ modification 3]

Fig. 11 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 1c according to modification 3 of the present embodiment.

The functional water concentration sensor 1c according to the present modification differs from the functional water concentration sensor 1 shown in fig. 1 in that a fluorescent material 20c is provided instead of the fluorescent material 20, and an emission window 42c is provided instead of the emission window 42 of the container 40.

The fluorescent material 20c is provided in the emission window 42c of the container 40. For example, the emission window 42c is formed of a phosphor-containing glass containing the phosphor 20 c. The emission window 42c contains dispersed phosphor particles.

As described above, according to the functional water concentration sensor 1c of the present modification, the fluorescent material 20c and the emission window 42c are shared, and therefore, the distance between the container 40 and the light receiving element 30 can be shortened. Accordingly, the functional water concentration sensor 1c can be downsized. Further, since stray light of the fluorescent light 21 emitted from the emission window 42c can be reduced, detection accuracy can be improved.

[ modification 4]

Fig. 12 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 1d according to modification 4 of the present embodiment.

The functional water concentration sensor 1d according to the present modification is different from the functional water concentration sensor 1 shown in fig. 1 in that a fluorescent material 20d is provided instead of the fluorescent material 20.

The fluorescent material 20d is provided on the surface of the light receiving element 30. Specifically, the fluorescent material 20d is contained in a resin material applied to the surface of the light receiving element 30. The resin material is a material having light transmittance, such as silicone resin.

As described above, according to the functional water concentration sensor 1d of the present modification, since the fluorescent material 20d is provided on the surface of the light receiving element 30, the amount of received light of the fluorescent light 21 emitted from the fluorescent material 20d can be increased. This can reduce stray light of the fluorescent light 21 emitted from the emission window 42c, and thus can improve detection accuracy. Further, since the distance between the container 40 and the light receiving element 30 can be shortened, the functional water concentration sensor 1d can be downsized.

(example 2)

Next, a functional water concentration sensor according to example 2 will be described with reference to fig. 13. Hereinafter, the differences from embodiment 1 will be mainly described, and the descriptions of the same parts as embodiment 1 will be omitted or simplified.

Fig. 13 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 2 according to the present embodiment. As shown in fig. 13, the functional water concentration sensor 2 is different from the functional water concentration sensor 1 shown in fig. 1 in that a reflection unit 70 is newly provided.

[ reflection part (first reflection part) ]

The reflection unit 70 is an example of a first reflection unit that is provided inside the container 40 and reflects the ultraviolet light 11. The reflection unit 70 specularly reflects the ultraviolet light 11. Specifically, the reflection unit 70 reflects the ultraviolet light 11 emitted from the light source 10 and passing through the entrance window 41 toward the fluorescent material 20. The reflected ultraviolet light 11 is irradiated to the fluorescent material 20 through the emission window 42, and excites the fluorescent material 20. The fluorescent material 20 emits fluorescent light 21 after excitation, and the fluorescent light 21 enters the light receiving element 30. Since the reflecting portion 70 is provided, the optical path length of the ultraviolet light 11 becomes approximately twice the width of the container 40 as shown in fig. 13.

The reflecting portion 70 is an inner surface of the container 40. Specifically, the inner surface of the container 40 is mirror-finished, thereby forming the reflection portion 70. For example, when the container 40 is made of a metal material, the inner surface is polished to be mirror-finished, thereby forming the reflection portion 70. When the container 40 is made of a resin material, a metal deposition film or the like is formed on the inner surface to form the reflection section 70.

The reflection unit 70 may be formed as a member different from the container 40. That is, the reflection unit 70 may be a reflection plate disposed at a predetermined position of the container 40. The reflection unit 70 may be, for example, a glass plate or a resin plate having a mirror-finished surface. The reflecting portion 70 is fixed to the inner surface of the container 40.

[ relationship between optical path length and concentration ]

Here, the results of measuring the relationship between the concentration and the transmittance for each optical path length when the functional water 90 is ozone water will be described with reference to fig. 14. Fig. 14 is a graph showing the transmittance of the ultraviolet light 11 with respect to the concentration of ozone water for each optical path length of the functional water concentration sensor 2 according to the present embodiment.

In fig. 14 (a) and (b), the horizontal axis shows the concentration of ozone water (functional water 90), and the vertical axis shows the transmittance of ultraviolet light 11. Fig. 14 (b) is an enlarged view of the range of 0 to 0.05mg/L ozone concentration and 0.96 to 1 transmittance (the dotted line frame of fig. 14 (a)).

As shown in fig. 14, it is known that the longer the optical path length L, the smaller the transmittance. The longer the optical path length, the longer the ultraviolet light 11 is transmitted, and the longer the functional water 90 is in contact with. Therefore, the amount of ultraviolet light 11 absorbed by the functional water 90 also increases, and the transmittance decreases.

This tendency occurs even when the concentration of ozone water is low. As shown in fig. 14 (b), even if the concentration of ozone water is low, the amount of change in transmittance increases, and therefore, the change in transmittance can be easily detected. That is, since the detection resolution is improved, the concentration of ozone water can be measured with high accuracy from the transmittance.

[ Effect and the like ]

As described above, the functional water concentration sensor 2 according to the present embodiment further includes the reflection unit 70 provided inside the container 40 and reflecting the ultraviolet light 11.

Accordingly, the ultraviolet light 11 is reflected inside the container 40 by the reflection unit 70 provided inside the container 40, and the optical path length of the ultraviolet light 11 can be increased. Therefore, even when the concentration of the functional water 90 is low and the absorbance is low, the change in the intensity of the ultraviolet light 11 can be detected by the light receiving element 30 because the optical path length of the ultraviolet light 11 is increased and a large amount of the ultraviolet light 11 is absorbed. That is, the measurement range of the concentration of the functional water 90 can be expanded. In this way, the range of the concentration that can be measured can be expanded without increasing the size of the functional water concentration sensor 2.

The reflection portion 70 is, for example, an inner surface of the container 40.

Accordingly, since the inner surface of the container 40 is used as the reflection portion 70, no other member is required, and the cost can be reduced. Further, as compared with the case where a reflecting plate or the like is provided as another member, the space in the container 40 can be effectively used, and for example, a longer optical path length can be secured.

The functional water concentration sensor 2 according to the present embodiment may not include the fluorescent material 20. That is, the light receiving element 30 may be a photodiode having sensitivity in the ultraviolet region, and may directly detect the ultraviolet light 11 transmitted through the functional water 90. In this case, according to the present embodiment, even without enlarging the size, the range of the concentration that can be measured can be enlarged, and the measurement accuracy can be improved. That is, the functional water concentration sensor 2 can be downsized, highly accurate, and highly sensitive.

Hereinafter, a modified example of the functional water concentration sensor 2 according to the present embodiment will be described with reference to the drawings. In the description of the respective modifications, the same points as those of the functional water concentration sensor 2 according to the present embodiment will be omitted or simplified.

[ modification 1]

Fig. 15 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 2a according to modification 1 of the present embodiment.

The functional water concentration sensor 2a according to the present modification is different from the functional water concentration sensor 2 shown in fig. 13 in that it includes a plurality of reflection portions 70. The plurality of reflection portions 70 are configured to reflect the ultraviolet light 11 a plurality of times.

Fig. 15 shows an example in which the functional water 90 flows in the container 40, that is, the container 40 is a part of a pipe forming a flow path for the functional water 90. The shape of the container 40, i.e., the shape of the pipe, is, for example, a cylinder or a square tube, but is not particularly limited. For example, in fig. 15, the functional water 90 flows in the up-down direction of the drawing. This is also the same for the following modified examples 2 to 5.

In the present modification, the functional water concentration sensor 2a includes three reflection portions 71 to 73 as the plurality of reflection portions 70. The functions, materials, and the like of the reflection portions 71 to 73 are similar to those of the reflection portion 70 shown in fig. 13. The

reflection portions

71 and 72 are provided on the surfaces of the inner surface of the container 40 corresponding to the light source 10 and the light receiving element 30, and the reflection portion 73 is provided on the surface of the inner surface of the container 40 on the same side as the light source 10 and the light receiving element 30.

The reflection unit 71 reflects the ultraviolet light 11 emitted from the light source 10 and passing through the entrance window 41 toward the reflection unit 73. The reflection unit 73 reflects the ultraviolet light 11 reflected by the reflection unit 71 toward the reflection unit 72. The reflection section 72 reflects the ultraviolet light 11 reflected by the reflection section 73 toward the fluorescent material 20. The ultraviolet light 11 reflected by the reflecting portion 72 is irradiated to the fluorescent material 20 through the emission window 42, and the fluorescent material 20 is excited.

As described above, the functional water concentration sensor 2a according to the present modification includes the plurality of first reflection units 70, and the plurality of reflection units 70 are arranged to reflect the ultraviolet light 11 a plurality of times.

Accordingly, since the ultraviolet light 11 is reflected by the three reflection portions 71 to 73 a plurality of times, the optical path length of the ultraviolet light 11 traveling inside the container 40 can be further increased. The optical path length is made longer, so that the concentration of the lighter functional water 90 can be measured. That is, the functional water concentration sensor 2a can have high sensitivity.

In the present modification, the entire inner surface of the container 40 may be mirror-finished.

[ modification 2]

Fig. 16 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 2b according to modification 2 of the present embodiment. The functional water concentration sensor 2b according to the present modification can change the arrangement position or orientation of the light source 10 and the light receiving element 30 according to the concentration of the functional water 90. Fig. 16 (a) shows a case where the concentration of the functional water 90 is high, and (b) shows a case where the concentration of the functional water 90 is low.

The functional water concentration sensor 2b according to the present modification is different from the functional water concentration sensor 2 shown in fig. 13 in that a control circuit 50b is provided instead of the control circuit 50. A reflection unit 70 is provided on the entire inner surface of the container 40. The reflecting portion 70 may be provided within a range irradiated with the ultraviolet light 11, instead of being provided on the entire inner surface of the container 40.

The control circuit 50b changes the arrangement position or orientation of at least one of the light source 10 and the light receiving element 30 in accordance with the concentration of the functional water 90, in addition to the function of the control circuit 50. At least one of the light source 10 and the light receiving element 30 is provided with a movable mechanism (not shown) such as an actuator, for example. The control circuit 50b changes the arrangement position or orientation of at least one of the light source 10 and the light receiving element 30 via the actuator. Accordingly, the control circuit 50b changes the optical path length from the light source 10 to the light receiving element 30. The optical path length corresponds to the length of the functional water 90 through which the ultraviolet light 11 passes, i.e., the distance from the entrance window 41 to the functional water 90 and then to the exit window 42.

Specifically, when the concentration of the functional water 90 is high, the control circuit 50b changes the arrangement position or orientation of the light source 10 or the light receiving element 30 so as to shorten the optical path length, as shown in fig. 16 (a). In the present modification, the control circuit 50b changes the direction of the light source 10 so that the number of reflections of the ultraviolet light 11 in the container 40 is reduced. Specifically, the control circuit 50b changes the direction of the light source 10 so that the incident angle of the ultraviolet light 11 emitted from the light source 10 with respect to the entrance window 41 becomes larger, that is, the ultraviolet light 11 is incident more obliquely with respect to the entrance window 41.

At this time, the control circuit 50b changes the direction of the light receiving element 30 in accordance with the direction of the ultraviolet light 11 emitted from the emission window 42. Specifically, the control circuit 50b changes the orientation of the light receiving element 30 so that the ultraviolet light 11 is incident perpendicularly to the light receiving surface. In the present embodiment, the fluorescent material 20 is provided, and the light receiving element 30 receives the fluorescent light 21 without receiving the ultraviolet light 11. Since the fluorescent material 20 emits the fluorescent light 21 in all directions, the control circuit 50b does not need to change the orientation of the light receiving element 30.

When the concentration of the functional water 90 is low, the control circuit 50b changes the arrangement position or orientation of the light source 10 or the light receiving element 30 so as to increase the optical path length, as shown in fig. 16 (b). In the present modification, the control circuit 50b changes the direction of the light source 10 so that the number of reflections in the ultraviolet light 11 container 40 increases. Specifically, the control circuit 50b changes the direction of the light source 10 so that the incident angle of the ultraviolet light 11 emitted from the light source 10 with respect to the entrance window 41 becomes small, that is, the ultraviolet light 11 is incident at an angle close to the perpendicular to the entrance window 41. In this case, the control circuit 50b may change the orientation of the light receiving element 30, but as described above, the fluorescence 21 is detected in the present modification, and thus, the change is not necessary.

Then, the control circuit 50b changes the arrangement position or orientation of the light source 10 or the light receiving element 30 based on the predicted value of the concentration of the functional water 90 (for example, the previous measured value) so that the optical path length from the light source 10 to the light receiving element 30 becomes an optical path length at which the concentration in the vicinity of the predicted value can be appropriately measured.

For example, if the concentration of the functional water 90 is too high, most of the ultraviolet light 11 is absorbed, and therefore the light receiving element 30 hardly receives the fluorescence 21. When the light receiving element 30 is almost unable to receive the fluorescence 21, the optical path length is shortened, so that the absorption of the ultraviolet light 11 by the functional water 90 can be suppressed, and the fluorescence 21 can be received by the light receiving element 30. Accordingly, the concentration of the more concentrated functional water 90 can be measured.

On the other hand, when the concentration of the functional water 90 is too low, the ultraviolet light 11 is hardly absorbed, and the amount of the fluorescence 21 detected by the light receiving element 30 is substantially the same as that in the case where the functional water 90 is not present. Alternatively, the light may exceed the detection region of the light receiving element 30 and be saturated. In this case, the optical path length is increased, and the functional water 90 is urged to absorb the ultraviolet light 11, so that the fluorescence 21 of an appropriate amount of light can be received by the light receiving element 30. Accordingly, the concentration of the lighter functional water 90 can be measured.

As described above, the functional water concentration sensor 2b according to the present modification further includes the control circuit 50b that changes the arrangement position or orientation of at least one of the light source 10 and the light receiving element 30 in accordance with the concentration of the functional water 90, thereby changing the optical path length from the light source 10 to the light receiving element 30.

This can improve the accuracy of measuring the concentration of the functional water 90, and can expand the measurement range.

[ modification 3]

Fig. 17 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 2c according to modification 3 of the present embodiment.

The functional water concentration sensor 2c according to the present modification is different from the functional water concentration sensor 2 shown in fig. 13 in that a slit portion 60c is newly provided.

The slit section 60c is provided between the light source 10 and the entrance window 41, and limits the irradiation range of the ultraviolet light 11. In the present modification, the slit portion 60c is an example of a collimating portion that converts the ultraviolet light 11 into parallel light. Specifically, the ultraviolet light 11 emitted from the light source 10 passes through the opening of the slit portion 60c and is emitted as parallel light. The slit portion 60c is, for example, a plate provided with an opening (slit).

The slit portion 60c is formed of a material that blocks (reflects or absorbs) the ultraviolet light 11. The slit portion 60c is formed of, for example, the same material as the main body of the container 40.

As described above, according to the functional water concentration sensor 2c according to the present modification, since the ultraviolet light 11 is converted into parallel light by the slit portion 60c, attenuation of the ultraviolet light 11 can be suppressed, and the use efficiency of the ultraviolet light 11 can be improved. This makes it possible to expand the range of concentration that can be measured, or to improve the accuracy of concentration measurement. In the present modification, for example, the collimating mechanism can be realized by a simple structure such as a plate provided with an opening, and therefore, the functional water concentration sensor 2c can be downsized and reduced in cost.

[ modification 4]

Fig. 18 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 2d according to modification 4 of the present embodiment.

The functional water concentration sensor 2d according to the present modification is different from the functional water concentration sensor 2 shown in fig. 13 in that a lens portion 61d is newly provided.

The lens unit 61d is provided between the light source 10 and the entrance window 41, and limits the irradiation range of the ultraviolet light 11. In the present modification, the lens portion 61d is an example of a collimating portion that converts the ultraviolet light 11 into parallel light. Specifically, the ultraviolet light 11 emitted from the light source 10 passes through the lens portion 61d and is emitted as parallel light. The lens portion 61d is a collimator lens, and is formed of, for example, translucent quartz glass.

As described above, according to the functional water concentration sensor 2d according to the present modification, since the ultraviolet light 11 is converted into parallel light by the lens portion 61d, attenuation of the ultraviolet light 11 can be suppressed, and the use efficiency of the ultraviolet light 11 can be improved. This makes it possible to expand the range of concentration that can be measured, or to improve the accuracy of concentration measurement. In addition, in the present modification, since the collimating mechanism can be realized with a simple configuration, the functional water concentration sensor 2d can be downsized and reduced in cost.

[ modification 5]

Fig. 19 is a schematic diagram for explaining the structure and operation of the functional water concentration sensor 2e according to modification 5 of the present embodiment.

The functional water concentration sensor 2e according to the present modification differs from the functional water concentration sensor 2 shown in fig. 13 in that a plurality of groups of light sources 10 and light receiving elements 30 are provided, and a control circuit 50e is provided instead of the control circuit 50.

In the present modification, the plurality of light sources 10 and the plurality of light receiving elements 30 form an array. For example, the plurality of light sources 10 are arranged in a one-dimensional array along the direction in which the functional water 90 flows. The plurality of light sources 10 may be arranged in a two-dimensional array or a three-dimensional array. The same applies to the plurality of light receiving elements 30.

As shown in fig. 19, the functional water concentration sensor 2e includes, as the plurality of light sources 10, light sources 10e1 and 10e 2. The functional water concentration sensor 2e includes light-receiving elements 30e1 and 30e2 as the plurality of light-receiving elements 30. The light sources 10e1 and 10e2 and the light receiving elements 30e1 and 30e2 have the same functions as the light source 10 and the light receiving element 30, respectively.

In the present modification, the light source 10e1 corresponds to the light receiving element 30e1, and the light source 10e2 corresponds to the light receiving element 30e 2. In other words, the light source 10e1 and the light receiving element 30e1 form one group (for example, a first group), and the light source 10e2 and the light receiving element 30e2 form another group (for example, a second group). Specifically, the ultraviolet light 11 emitted from the light source 10e1 enters the light receiving element 30e1, and the ultraviolet light 11 emitted from the light source 10e2 enters the light receiving element 30e 2.

The plurality of groups of light sources 10 and light receiving elements 30 are arranged so that the optical path lengths from the light sources 10 to the corresponding light receiving elements 30 are different from each other. As shown in fig. 19, the optical path length of one group (first group) of the light source 10e1 and the light receiving element 30e1 is longer than the optical path length of one group (second group) of the light source 10e2 and the light receiving element 30e 2.

The control circuit 50e selectively changes the plurality of groups of the light source 10 and the light receiving element 30 according to the concentration of the functional water 90 in addition to the function of the control circuit 50. Accordingly, the control circuit 50e changes the optical path length in accordance with the concentration of the functional water 90.

For example, when the concentration of the functional water 90 is high, the control circuit 50e selects a group (first group) of the light source 10e1 and the light receiving element 30e1 having a long optical path length. On the contrary, when the concentration of the functional water 90 is low, the control circuit 50e selects the group (second group) of the light source 10e2 and the light receiving element 30e2 having a short optical path length.

As described above, the functional water concentration sensor 2e according to the present modification includes a plurality of groups of the light sources 10 and the light receiving elements 30, the plurality of groups of the light sources 10 and the light receiving elements 30 are arranged such that the optical path lengths from the light sources 10 to the corresponding light receiving elements 30 are different from each other, and the functional water concentration sensor 2e further includes the control circuit 50e for selectively changing the number of groups in accordance with the concentration of the functional water 90.

Accordingly, as in the case of changing the arrangement position or orientation of the light source 10 or the light receiving element 30 (modification 2 of the present embodiment), an appropriate group is selected according to the density, and an appropriate optical path length can be selected. Therefore, the accuracy of measuring the concentration of the functional water 90 can be improved, and the measurement range can be expanded.

(example 3)

Next, a functional water concentration sensor according to example 3 will be described with reference to fig. 20. Hereinafter, the differences from embodiment 1 will be mainly described, and the descriptions of the same parts as embodiment 1 will be omitted or simplified.

Fig. 20 is a schematic diagram showing a configuration for explaining the functional water concentration sensor 3 according to the present embodiment. Specifically, (a) of fig. 20 is a sectional view of the functional water concentration sensor 3, showing a section orthogonal to the direction in which the functional water 90 flows in the container 40 constituting a part of the piping. Fig. 20 (b) shows a section of line XX-XX of (a). That is, the functional water 90 flows in the depth direction of the drawing in (a) and flows in the vertical direction of the drawing in (b) (see the white arrow line).

As shown in fig. 20, the functional water concentration sensor 3 is different from the functional water concentration sensor 1 according to embodiment 1 in that a reflection unit 80 is newly provided.

[ reflection part (second reflection part) ]

The reflection unit 80 is an example of a second reflection unit having a reflection surface on which the fluorescent material 20 is provided, and reflecting the fluorescent light 21 toward the light receiving element 30 by the reflection surface. The reflection unit 80 is provided outside the container 40.

Specifically, the reflection unit 80 is a reflection plate provided outside the container 40. The reflection unit 80 is, for example, a glass plate or a resin plate having a mirror-finished surface on at least one principal surface (reflection surface). The reflecting surface of the reflecting portion 80 is coated with a resin material containing the fluorescent material 20.

In the present embodiment, the example in which the resin material containing the fluorescent material 20 is applied to the reflective surface is shown, but the present invention is not limited to this. A glass plate or the like containing the phosphor 20 may be attached to the reflecting surface.

[ Effect and the like ]

As described above, the functional water concentration sensor 3 according to the present embodiment further includes the reflection unit 80 having the reflection surface on which the fluorescent material 20 is provided, provided outside the container 40, and reflecting the fluorescent light 21 toward the light receiving element 30 by the reflection surface.

For example, according to the configuration shown in embodiment 1 and the like, substantially half of the fluorescent light 21 emitted from the fluorescent material 20 is emitted to the emission window 42 side without being incident on the light receiving element 30. In contrast, in the present embodiment, since the reflection unit 80 reflects the fluorescent light 21 toward the light receiving element 30, a larger amount of fluorescent light 21 can be made incident on the light receiving element 30. This makes it possible to effectively utilize the fluorescent light 21 emitted from the fluorescent material 20. Therefore, even when the intensity of the ultraviolet light 11 is weak and the intensity of the fluorescence 21 is weak, the light receiving element 30 can receive a large amount of light, and thus the concentration of the functional water 90 can be measured. That is, the measurable range of the concentration of the functional water 90 can be expanded.

Hereinafter, a modified example of the functional water concentration sensor 3 according to the present embodiment will be described with reference to the drawings. In the description of the respective modifications, the same points as those of the functional water concentration sensor 3 according to the present embodiment will be omitted or simplified.

[ modification 1]

Fig. 21 is a schematic diagram showing the structure of the functional water concentration sensor 3a according to modification 1 of the present embodiment. Specifically, (a) of fig. 21 shows a cross section perpendicular to the direction in which the functional water 90 flows in the container 40 constituting a part of the pipe of the functional water concentration sensor 3a, and (b) shows a cross section of line XXI-XXI of (a).

The functional water concentration sensor 3a according to the present modification is different from the functional water concentration sensor 3 shown in fig. 20 in that a slit portion 60c is newly provided. The slit portion 60c is the same as that of the modification 3 of the embodiment 2.

As described above, according to the functional water concentration sensor 3a according to the present modification, since the ultraviolet light 11 is converted into parallel light by the slit portion 60c, attenuation of the ultraviolet light 11 can be suppressed, and the use efficiency of the ultraviolet light 11 can be improved. This makes it possible to expand the range of concentration that can be measured, or to improve the accuracy of concentration measurement. In the present modification, for example, the collimating mechanism can be realized by a simple structure such as a plate provided with an opening, and therefore, the functional water concentration sensor 3a can be downsized and reduced in cost.

[ modification 2]

Fig. 22 is a schematic diagram showing the structure of the functional water concentration sensor 3b according to modification 2 of the present embodiment. Specifically, fig. 22 (a) shows a cross section perpendicular to the direction in which the functional water 90 flows in the container 40 constituting a part of the pipe of the functional water concentration sensor 3b, and (b) shows a cross section along the line XXII-XXII in (a).

The functional water concentration sensor 3b according to the present modification is different from the functional water concentration sensor 3 shown in fig. 20 in that a lens portion 61d is newly provided. The lens portion 61d is the same as the lens portion shown in modification 4 of embodiment 2.

As described above, according to the functional water concentration sensor 3b of the present modification, the lens portion 61d converts the ultraviolet light 11 into parallel light, so that the attenuation of the ultraviolet light 11 can be suppressed, and the use efficiency of the ultraviolet light 11 can be improved. This makes it possible to expand the range of concentration that can be measured, or to improve the accuracy of concentration measurement. In addition, in the present modification, since the collimating mechanism can be realized with a simple configuration, the functional water concentration sensor 3b can be downsized and can be reduced in cost.

[ modification 3]

Fig. 23 is a schematic diagram showing the structure of a functional water concentration sensor 3c according to modification 3 of the present embodiment. Specifically, fig. 23 shows a cross section perpendicular to the direction in which the functional water 90 flows in the container 40 constituting a part of the pipe of the functional water concentration sensor 3 c.

The functional water concentration sensor 3c according to the present modification is different from the functional water concentration sensor 3 shown in fig. 20 in that a reflection unit 80c is provided instead of the reflection unit 80.

The reflection portion 80c is a concave mirror. Specifically, the reflection unit 80c is an elliptical mirror having a focal point at the light receiving element 30. That is, the reflection surface of the reflection portion 80c is a part of an elliptical surface. The reflecting portion 80c may be a parabolic mirror having a parabolic reflecting surface.

Accordingly, a larger amount of fluorescence 21 can be incident on the light receiving element 30, and therefore, the measurable range of the concentration of the functional water 90 can be expanded.

(others)

The functional water concentration sensor according to the present invention has been described above with reference to the above-described embodiment and its modified examples, but the present invention is not limited to the above-described embodiment.

For example, although the light source 10 and the light receiving element 30 are disposed outside the container 40 in the above embodiment, the present invention is not limited thereto. For example, the light source 10 may be mounted on the entrance window 41. That is, the light-emitting surface of the light source 10 may be exposed in the container 40. Similarly, the light receiving element 30 may be attached to the emission window 42. That is, the light receiving surface of the light receiving element 30 may be exposed in the container 40. In this case, the phosphor 20 is also disposed in the container 40. Alternatively, the light source 10 and the light receiving element 30 may be disposed inside the container 40. In this case, the container 40 may not include the entrance window 41 and the exit window 42.

The present invention also includes an embodiment obtained by implementing various modifications of the embodiments, and an embodiment obtained by arbitrarily combining the constituent elements and functions of the embodiments without departing from the scope of the present invention.

Description of the symbols

1. 1a, 1b, 1c, 1d, 2a, 2b, 2c, 2d, 2e, 3a, 3b, 3c functional water concentration sensor

10. 10e1, 10e2 light source

11 ultraviolet light

20. 20c, 20d phosphor

21 fluorescence

30. 30e1, 30e2 light-receiving element

40 container

41 entrance window

42. 42c exit window

50. 50b, 50e control circuit

60. 60c slit part

61. 61d lens unit

70. 71, 72, 73 reflection part (first reflection part)

80. 80c reflection part (second reflection part)

90 functional water

Claims

1. A functional water concentration sensor having a sterilization function, comprising:

a container into which functional water is put;

a light source emitting ultraviolet light;

a phosphor excited by ultraviolet light emitted from the light source and passing through the inside of the container, thereby emitting fluorescence; and

a light receiving element for receiving the fluorescence,

the peak wavelength of the ultraviolet light emitted by the light source is within a predetermined range including an absorption peak specific to the functional water,

the functional water concentration sensor further comprises a first reflection part,

the first reflection part is provided inside the container and reflects the ultraviolet light,

the functional water concentration sensor is also provided with a control circuit,

the control circuit changes the arrangement position or orientation of at least one of the light source and the light receiving element according to the last measured value of the concentration of the functional water, thereby changing the optical path length from the light source to the light receiving element,

the container is provided with:

a body formed of a material shielding the ultraviolet light;

an entrance window to which the ultraviolet light emitted from the light source is incident; and

an emission window formed of a phosphor-containing glass containing the phosphor,

the functional water concentration sensor measures the concentration of the functional water while circulating the functional water.

2. The functional water concentration sensor according to claim 1,

the fluorescent material emits light having a peak wavelength corresponding to the sensitivity of the light receiving element as the fluorescent light.

3. The functional water concentration sensor according to claim 1,

the light receiving element is disposed in proximity to the phosphor.

4. The functional water concentration sensor according to any one of claims 1 to 3,

the light source, the entrance window, the exit window, and the light receiving element are arranged in this order on substantially the same straight line.

5. The functional water concentration sensor according to claim 1,

the functional water concentration sensor includes a plurality of first reflecting portions,

the plurality of first reflection portions are configured to reflect the ultraviolet light a plurality of times.

6. The functional water concentration sensor according to claim 1,

the first reflecting portion is an inner surface of the container.

7. The functional water concentration sensor according to claim 1,

the functional water concentration sensor includes a plurality of groups of the light source and the light receiving element,

the plurality of groups of the light sources and the light receiving elements are arranged so that optical path lengths from the light sources to the corresponding light receiving elements are different from each other,

the control circuit selectively changes the plurality of groups in accordance with the concentration of the functional water.

8. The functional water concentration sensor according to claim 1,

the functional water concentration sensor is also provided with a second reflection part,

the second reflecting unit is provided outside the container, has a reflecting surface on which the fluorescent material is provided, and reflects the fluorescent light toward the light receiving element by the reflecting surface.

9. The functional water concentration sensor according to claim 8,

the second reflecting portion is a concave mirror.

10. The functional water concentration sensor according to claim 9,

the second reflecting section is an elliptical mirror having a focal point at the light receiving element.

11. The functional water concentration sensor according to claim 1,

the functional water concentration sensor is also provided with a slit part,

the slit portion is disposed between the light source and the entrance window, and limits an irradiation range of the ultraviolet light.

12. The functional water concentration sensor according to claim 11,

the slit portion has an opening having substantially the same shape as the entrance window.

13. The functional water concentration sensor according to claim 1,

the functional water concentration sensor is also provided with a lens part,

the lens unit is provided between the light source and the entrance window, and suppresses divergence of the ultraviolet light.

14. The functional water concentration sensor according to claim 1,

the functional water concentration sensor is also provided with a collimation part,

the collimating part is disposed between the light source and the entrance window, and converts the ultraviolet light into parallel light.

15. The functional water concentration sensor according to claim 1,

ultraviolet light from the light source is incident substantially perpendicularly to the entrance window.